The present invention relates to a drill guide apparatus for locating and installing a transverse pin for holding a ligament replacement in a tunnel of a receptor bone. More particularly, the present invention relates to a drill guide apparatus for aligning the pin relative to the tunnel so that the pin intersects the tunnel and the ligament replacement to secure the ligament replacement to the bone to promote healing and bonding of the ligament replacement.
When a ligament such as an anterior cruciate ligament (ACL) of a knee is damaged or torn, a replacement ligament is often installed in the knee to reconstruct the natural anterior cruciate ligament. During such reconstruction, a tunnel is typically drilled through the anterior portion of the tibia upwardly through the tibial plateau and into the distal end of the femur to approximate the natural position of the anterior cruciate ligament. A bone-ligament-bone graft is then harvested, often from the patellar tendon following standard grafting procedures. Typically a wedge-shaped graft is cut and contoured using a graft guide. Sutural holes are then formed in the graft. The graft is then installed into the drill tunnel.
Various methods are known for securing the graft within the tibia and femur until the graft can heal. One such method is the use of a Kurosaka.TM. fixation screw. The Kurosaka.TM. screw provides an interference fit inside the tunnel with the graft so that the graft is wedged against the wall of the tunnel. See, for example, U.S. Pat. No. 4,950,270.
In other known methods, sutures coupled to the graft are anchored to the bone using screws or washers. The ligaments can also be coupled directly to the bone using plates or washers.
The prior art also includes several different types of drill guides for forming tunnels in the femur and tibia for aligning and installing transverse pins to anchor ligament replacements. One example is U.S. Pat. No. 4,901,711 which shows such a drill guide which mounts on a K-wire after it is inserted into the knee joint. The K-wire exits the knee joint at a point below the tibia and at another point above the femur. The drill guide of the '711 patent is journalled on the K-wire so that the guide is rotatable about the axis of the K-wire. The guide then has a drill sleeve which moves longitudinally parallel to the axis of the K-wire to a selected point to locate a transverse anchoring pin. The drill guide of the present invention is an improvement over the drill guide shown in the '711 patent because the guide is mounted only below the tibia plateau on the shank of the tunnel drill and, of course, the tunnel itself is drilled before the guide used. The drill guide of the present invention uses the tunnel drill as a reference to locate and install a transverse anchoring pin at a selected point. This selected point is established on the drill itself such that the drill guide, when mounted on the drill, and moved to an appropriate scale point on the drill, will locate the transverse pin at an appropriate location below the uppermost end of the tunnel.
Another example is U.S. Pat. No. 4,985,032 which shows a drill guide for locating transverse pins for holding ligaments in tunnels formed in knee joints, particularly to replace the ACL. The U-shaped guide of the '032 patent is used with one leg of the guide inserted upwardly through the tunnel after the drill is removed. Use of the U-shaped guide of the '032 patent requires extra steps which are eliminated by using the tunnel drill itself as a mount for the drill guide. The tunnel drill of the present invention is provided with scale means so that the surgeon will know exactly where the uppermost end of the drill and tunnel are and where the transverse pin has to be located in the femur properly to intersect any ligament replacement placed in the tunnel and pulled upwardly to that innermost end.
The drill guide apparatus of the present invention therefore provides several advantages over these known drill guides. One advantage is that the drill guide of the present invention uses the tunnel drill which forms the tunnel in a bone as a reference axis for establishing the position of transverse guide pins which intersect the tunnel and the replacement ligament to secure the replacement ligament to the bone. The tunnel drill provides a stable reference axis for aligning the pins to intersect the tunnel. In addition, the drill guide can be used right after the tunnel is formed in the bone without the need to insert another rod or other apparatus into the tunnel of the bone.
According to one aspect of the present invention, a drill guide is provided for aligning and installing a transverse pin through a tunnel formed by a tunnel drill in a bone to secure a ligament replacement to the bone. The drill guide includes an arm member and a drill guide sleeve coupled to the arm member. The drill guide sleeve is formed to include a central bore for guiding a drill to form a transverse guide hole in the bone to guide insertion of the transverse pin into the bone. The central bore of the drill guide sleeve has an axis which is aligned to intersect the tunnel. The drill guide also includes means for coupling the arm member to the tunnel drill while the tunnel drill is still in the bone to align the arm member and drill guide sleeve at a desired anatomical location using the tunnel drill in the bone as a reference.
In the illustrated embodiment, the drill guide has generally L-shaped body including a first arm extending in a direction normal to the tunnel drill and a second arm having a proximal end coupled to the first arm so that the second arm extends generally parallel to the tunnel drill and a distal end. The drill guide sleeve is coupled to the distal end of the second arm.
Also in the illustrated embodiment, the coupling means includes means for mounting the arm member on the tunnel drill for movement longitudinally along an axis of the tunnel drill to position the drill guide sleeve relative to an uppermost end of the tunnel drill and the tunnel end formed thereby. The arm member is also rotatable about the tunnel drill axis to position the drill guide sleeve to a selected anatomical position relative to the bone. The drill guide also includes means for indicating the position of the drill guide sleeve relative to an uppermost end of the tunnel drill which corresponds to an end of the tunnel.
According to another aspect of the invention, the drill guide further comprises a second drill guide sleeve slidably coupled to the arm member of the drill guide. The second drill guide sleeve is formed to include a central bore for guiding the drill to form a second transverse guide hole in the bone to guide insertion of a second transverse pin into the bone. The central bore of the second drill guide sleeve has an axis which is aligned to intersect the tunnel.
In the illustrated embodiment, the arm member of the drill guide is twisted at a predetermined angle to align the second guide sleeve relative to the tunnel drill so that the axis of the second guide sleeve intersects the tunnel. The drill guide further includes means for indicating the distance between the first and second drill guide sleeves.
According to yet another aspect of the invention, the drill guide sleeve is coupled to the arm member by a ratchet mechanism for selectively axially positioning the drill guide sleeve relative to said arm member. In the illustrated embodiment, the ratchet mechanism includes a spring loaded cog configured to engage the drill guide sleeve. The spring loaded cog permits axial movement of the drill guide sleeve relative to the arm member in a direction toward the bone and prevents axial movement of the drill guide sleeve relative to the arm member in a direction away from the bone. The drill guide sleeve is formed to include a plurality of teeth for engaging the spring loaded cog to lock the drill guide sleeve in a selected axial position relative to the arm member. The second drill guide sleeve is also coupled to the arm member by a ratchet mechanism for selectively axially positioning the second drill guide sleeve relative to said arm member.
The drill guide apparatus of the present invention is used to locate and install transverse pins for holding a ligament replacement in a tunnel formed in a bone with the pin intersecting the tunnel and the ligament replacement. When used to secure a replacement ligament for an anterior cruciate ligament, the tunnel is drilled through the tibia plateau upwardly into the distal end of the femur.
The drill guide is installed over the drill used in the tunnel drilling step. The drill guide is rotatable about the axis of the tunnel drill. The drill guide has a journal end mounted on the drill and an upwardly extending arm terminating with a transverse guide opening having an axis intersecting the axis of the tunnel drill. The position of the drill guide is adjusted longitudinally on the drill to position the axis of the transverse guide opening relative to the uppermost end of the tunnel corresponding to a preselected point at upper end of the drill to intersect the ligament replacement in the tunnel. The position of the drill guide is also adjusted by pivoting the drill guide about the axis of the axis of the drill to find a desired anatomical location for inserting the transverse pin into the femur. A drill sleeve in the transverse guide opening is then moved into engagement with the femur. Using the drill sleeve as a guide and using a first drill having a first diameter, a transverse guide hole is drilled transversely into the femur a predetermined distance stopping short of the tunnel to provide a transverse guide hole. The first drill is then removed from the drill sleeve, and a second drill having a second diameter larger than the first diameter is then inserted into the guide hole. The drill sleeve is then removed from the drill guide, leaving the second drill in place in the guide hole in the femur.
If it is desired to insert a transverse pin through the replacement ligament in the tibia, the position of the drill guide is adjusted about the axis of the drill to position a tibia drill guide at a desired anatomical location for inserting the second transverse pin into the tibia. A drill sleeve of the tibia drill guide is inserted in a second transverse guide opening provided on said upwardly extending arm and moved into engagement with the tibia. Using the drill sleeve as a guide and using the first drill having the first diameter, a transverse guide hole is drilled in the tibia a predetermined distance short of the tunnel. The first drill is then removed from the drill sleeve. A third drill having a diameter substantially equal to the second and larger diameter is then inserted into the guide hole of the tibia. The drill sleeve is then removed leaving the third drill in place in the guide hole in the tibia.
The drill guide and the tunnel drill are removed from the knee and the ligament replacement is inserted into the tunnel in the femur and tibia. A soft tissue protector is installed over the second drill to engage the femur. Then, using the second drill, a hole is drilled through the femur, the tunnel, the ligament replacement and on into the femur on an opposite side of the tunnel. The second drill is then removed leaving the soft tissue protector. Finally, the transverse pin is inserted through soft tissue protector, the guide hole, the tunnel, the ligament replacement therein, and on into the femur on an opposite side of the tunnel to anchor the ligament replacement in the femur.
A soft tissue protector is then inserted over the third drill to engage the tibia. Using the third drill, a hole is drilled through the tibia, the tunnel in the tibia, the ligament replacement and on into the tibia on an opposite side of the tunnel. The third drill is then removed leaving the soft tissue protector. The transverse pin is then inserted through the soft tissue protector, the tibia guide hole, the tunnel, the ligament replacement therein and on into the tibia on an opposite side of the tunnel, to anchor the ligament replacement in the tibia.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.